Wireless telephone antenna diversity system and method

ABSTRACT

A system and method are provided for diversifying radiated electromagnetic communications in a wireless communication device having a plurality of embedded antennas. The method comprises sensing conducted electromagnetic transmission line signals communicated by the antennas, selecting between the antennas in response to sensing the transmission line signals, and modifying antenna electrical performance characteristics in response to sensing the transmission line signals. In some aspects sensing transmission line signals includes sensing transmission line signal power levels. For example, the power levels of the radiated signals conducted on the transmission lines can be sensed or the transmission line signal power levels of transmitted signals reflected by the antennas are sensed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation application of application Ser. No. 10/407,606,filed Apr. 3, 2003 now U.S. Pat. No. 6,924 766, the disclosure of whichis hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to wireless communication deviceantennas and, more particularly, to a system and method for usingchassis-embedded antennas to diversify radiated electromagnetic signalscommunicated by a wireless communications device.

2. Description of Related Art

The size of portable wireless communications devices, such astelephones, continues to shrink, even as more functionality is added. Asa result, the designers must increase the performance of components ordevice subsystems while reducing their size, or placing these componentsin less desirable locations. One such critical component is the wirelesscommunications antenna. This antenna may be connected to a telephonetransceiver, for example, or a global positioning system (GPS) receiver.

Wireless telephones can operate in a number of different frequencybands. In the US, the cellular band (AMPS), at around 850 megahertz(MHz), and the PCS (Personal Communication System) band, at around 1900MHz, are used. Other frequency bands include the PCN (PersonalCommunication Network) at approximately 1800 MHz, the GSM system (GroupeSpeciale Mobile) at approximately 900 MHz, and the JDC (Japanese DigitalCellular) at approximately 800 and 1500 MHz. Other bands of interest areGPS signals at approximately 1575 MHz and Bluetooth at approximately2400 MHz.

Conventionally, good communication results have been achieved using awhip antenna. Using a wireless telephone as an example, it is typical touse a combination of a helical and a whip antenna. In the standby modewith the whip antenna withdrawn, the wireless device uses the stubby,lower gain helical coil to maintain control channel communications. Whena traffic channel is initiated (the phone rings), the user has theoption of extending the higher gain whip antenna. Some devices combinethe helical and whip antennas. Other devices disconnect the helicalantenna when the whip antenna is extended. However, the whip antennaincreases the overall form factor of the wireless telephone.

It is known to use a portion of a circuitboard, such as a dc power bus,as an electromagnetic radiator. This solution eliminates the problem ofan antenna extending from the chassis body. Printed circuitboard, ormicrostrip antennas can be formed exclusively for the purpose ofelectromagnetic communications. These antennas can provide relativelyhigh performance in a small form factor.

Since not all users understand that an antenna whip must be extended forbest performance, and because the whip creates an undesirable formfactor, with a protrusion to catch in pockets or purses,chassis-embedded antenna styles are being investigated. That is, theantenna, whether it is a whip, patch, or a related modification, isformed in the chassis of the phone, or enclosed by the chassis. Whilethis approach creates a desirable telephone form factor, the antennabecomes more susceptible to user manipulation and other user-inducedloading effects. For example, an antenna that is tuned to operate in thebandwidth between 824 and 894 megahertz (MHz) while laying on a table,may be optimally tuned to operate between 790 and 830 MHz when it isheld in a user's hand. Further, the tuning may depend upon the physicalcharacteristics of the user and how the user chooses to hold and operatetheir phones. Thus, it may be impractical to factory tune a conventionalchassis-embedded antenna to account for the effects of usermanipulation.

It would be advantageous if a wireless communications device could sensedegradations in the tuning of a chassis-embedded antenna, due to effectof user manipulation for example.

It would be advantageous if a wireless communications device used asystem of chassis-embedded antennas to maximize antenna diversity.

It would be advantageous if the wireless communications devicechassis-embedded antenna system could be modified to account for theeffects of user manipulation or other antenna detuning mechanisms.

BRIEF SUMMARY OF THE INVENTION

The present invention describes a wireless communications devicechassis-embedded antenna system and method for improving the diversityof radiated electromagnetic communications. Because chassis-embedded orinternal antennas are more susceptible to degradation due to usermanipulating, the system uses a plurality of antennas that can beselected in response to monitoring the quality of communications througheach antenna.

Accordingly, a method is provided for diversifying radiatedelectromagnetic communications in a wireless communication device. Themethod comprises: mounting a first antenna and a second antenna internalto a wireless communication device chassis; sensing conductedelectromagnetic transmission line signals communicated by the first andsecond antennas; and, selecting between the first and second antennas inresponse to sensing the transmission line signals. In some aspects ofthe method, a single antenna is not selected, but rather, the first andsecond antennas are combined.

In some aspects of the method, sensing transmission line signalsincludes sensing transmission line signal power levels. For example, thetransmission line signal power levels of transmitted signals reflectedby the antennas are sensed. In other aspects, sensing transmission linesignals includes sensing the radiated signals received at the first andsecond antennas and conducted on the transmission line. For example, thepower levels of the radiated signals conducted on the transmission linescan be sensed. Then, antenna selection is responsive to the radiatedsignal transmission line signal power levels. Alternately, the radiatedsignals are received and decoded. Then, the antenna supplying thetransmission line signal with the fewest number of decoding errors isselected.

Other aspects of the method comprise: communicating radiatedelectromagnetic signals through the first antenna at a first operatingfrequency; and, communicating radiated electromagnetic signals throughthe second antenna at the first operating frequency. In one aspect, thefirst and second antennas are separated by an effective distance ofabout a quarter-wavelength of the first operating frequency, to createspatial diversity. In other aspects, the first antenna radiates in afirst polarized radiation pattern and the second antenna radiates in asecond polarized radiation pattern, orthogonal to the first polarizedradiation pattern.

Additional details of the above-described method and a wirelesstelephone antenna diversity system are provided in more detail below.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic block diagram of the present invention wirelesstelephone antenna diversity system.

FIG. 2 is a schematic block diagram illustrating a variation of thepresent invention system of FIG. 1.

FIG. 3 is a drawing showing an exemplary antenna mounting arrangement,featuring antenna spatial diversity.

FIG. 4 is a drawing showing an exemplary antenna mounting arrangement,featuring antenna polarity diversity.

FIG. 5 is a drawing illustrating the physical dimensions of the chassisof FIGS. 1 through 4.

FIG. 6 is a schematic block diagram illustrating a phase shift variationof the present invention system.

FIG. 7 is a schematic block diagram illustrating an antenna electricallength variation of the present invention system.

FIG. 8 is a flowchart illustrating the present invention method fordiversifying radiated electromagnetic communications in a wirelesstelephone device.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic block diagram of the present invention wirelesstelephone antenna diversity system. The system 100 comprises a chassis102 (represented as a dotted line), a first transmission line 104, asecond transmission line 106, and a first antenna 108 mounted internalto the chassis 102 with a transmission line port connected to the firsttransmission line 104. A second antenna 110 is mounted internal to thechassis 102 with a transmission line port connected to the secondtransmission line 106.

A regulator circuit 112 has an input operatively connected to the firsttransmission line 104 on line 113 and an input operatively connected tothe second transmission line 106 on line 114. As used herein, the phrase“operatively connected” means indirectly connected or connected throughan intervening element. The regulator circuit 112 has an output on line115 to supply control signals responsive to conducted electromagnetictransmission line signals on the first and second transmission lines104/106. A switch 116 has a transceiver connection port on line 118, aport connected to the first transmission line 104, a port connected tothe second transmission line 106, and an input to accept control signalsfrom the regulator circuit on line 115. The switch 116 selectivelyconnects the transceiver port on line 118 to the first and secondtransmission lines 104/106 in response to the control signals on line115.

In one aspect of the system 100, the switch 116 is literally a switchthat permits a transceiver to be connected to one of the antennas. Inother aspects of the system 100, the switch also acts as a combiner.That is, the switch 116 can combine (signals to and from) the first andsecond transmission ports, and connect the combined ports to thetransceiver port in response to control signals on line 115. Forexample, the switch 116 can incorporate a conventional 3 dB splitter.

Generally, the regulator circuit 112 supplies control signals on line115 responsive to transmission line signal power levels conducted on thefirst and second transmission lines 104/106. In one aspect of the system100, the regulator circuit 112 supplies control signals on line 115 thatare responsive to transmission line signal power levels reflected fromthe first antenna port and the second antenna port. That is, theregulator circuit 112 selects an antenna in response to measuringantenna mismatch. The antenna mismatch may be responsive to user handeffects and/or the relationship between the transmission frequency andthe optimal tuning range of the antenna.

Alternately, antenna selection decisions can be based upon the strengthof the signals that are received on the antennas 108/110. That is, thefirst antenna 108 receives radiated signals and supplies conductedtransmission line signals on the first transmission line 104. The secondantenna 110 receives radiated signals and supplies conductedtransmission line signals on the second transmission line 106. Then, thesystem 100 would further comprise a first power detector 120 having aninput operatively connected to the first transmission line 104 on line113 a and an output connected to the regulator circuit 112 on 113 b tosupply transmission line signal power levels. Likewise, a second powerdetector 122 would have an input operatively connected to the secondtransmission line 106 on line 114 a and an output connected to theregulator circuit 112 on 114 b to supply transmission line signal powerlevels. Alternately but not shown, a single power detector interposedbetween the switch and the transceiver could be multiplexed to samplethe signals on the two transmission lines. Either way, the regulatorcircuit 112 supplies control signals on line 115 that are responsive tothe first and second transmission line detected signal power levels.

FIG. 2 is a schematic block diagram illustrating a variation of thepresent invention system 100 of FIG. 1. As above, the first antenna 108receives radiated signals and supplies conducted transmission linesignals on the first transmission line 104. The second antenna 110receives radiated signals and supplies conducted transmission linesignals on the second transmission line 106. A receiver 200 has an inputconnected to the switch transceiver port on line 118 to receive anddecode the transmission line signals. The receiver 200 has an output online 202 connected to the regulator circuit 112 to supply decoded signalerror signals corresponding to each antenna. Then, the regulator circuit112 supplies control signals on line 115 that are responsive to thedecoded error signals for each antenna.

Note that system of FIG. 2 does not exclude any particular modulationscheme or coding format. Further, the system 100 can be used withmodulation schemes that use forward error correction (FEC) schemes. Inother aspect of the system 100, the antenna selections are made by acommunication partner, a wireless telephone base station for example.Then, the regulator circuit makes antenna selection decisions inresponse to commands that are received by receiver 200.

With respect to either FIG. 1 or FIG. 2, the first antenna 108 includesan active element with a first electric length and the second antenna110 includes an active element with a second electrical length. Notethat the first and second electrical lengths may be the same, tocommunicate at the same frequency. In other aspects, the electricallength may be different to communicate at different frequencies, orslightly offset, to communicate at different ends of a frequencybandwidth. The active element is defined by the antenna style. Forexample, a dipole antenna will have a radiator and a counterpoise,typically with effective electrical lengths that are each an effectivequarter-wavelength multiple of the operating frequency. The electricallengths are dependent upon the proximate dielectric material, as thewavelength of a conducted signal varies with the conducting medium. Amonopole antenna will have a groundplane counterpoise and a radiatorwith an effective electrical length that is an effectivequarter-wavelength multiple of the operating frequency. The presentinvention system 100 can be enabled with any convention antenna thatmeets the form factor of the chassis 102, and the present invention isnot limited to any particular antenna style.

FIG. 3 is a drawing showing an exemplary antenna mounting arrangement,featuring antenna spatial diversity. In some aspects, the first antenna108 has a first operating frequency responsive to the first electricallength 300 and the second antenna 110 has a first operating frequencyresponsive to the second electrical length 302 being equal to the firstelectrical length 300. The chassis 102 has a first position 304 formounting the first antenna 108 and a second position 306 for mountingthe second antenna 110. The first and second positions 304/306 beingseparated by an effective distance 308 of about a quarter-wavelength ofthe first operating frequency.

FIG. 4 is a drawing showing an exemplary antenna mounting arrangement,featuring antenna polarity diversity. The first antenna 108 has a firstoperating frequency responsive to the first electrical length 300 and afirst polarized radiation pattern represented by reference designator400. The second antenna 110 has a first operating frequency responsiveto the second electrical length 302 being equal to the first electricallength 302, and a second polarized radiation pattern represented byreference designator 402. The chassis 102 has a first position 404 formounting the first antenna 108 and a second position 406 for mountingthe second antenna 110. The first polarized radiation pattern 400 isorthogonal to the second polarized radiation pattern 402. Note that thepolarization patterns need not orthogonal, but orthogonality typicallyresults in better diversity. It should also be noted that thepolarization pattern is dependent upon the style of the antenna as wellas the placement of the antenna in the chassis.

FIG. 5 is a drawing illustrating the physical dimensions of the chassis102 of FIGS. 1 through 4. The chassis has a size of 4 inches (length),by 2 inches (width), by one inch (thickness), or less (in any of theabove-mentioned dimensions). Alternately stated, the chassis 102 has avolume of 8 cubic inches, or less. Although depicted as having abrick-like shape, it should be noted that the present invention is notlimited to any particular shape. It should also be noted that even abrick-shaped chassis will have variations to accommodate features suchas internal components, handgrip, display, keypad, and externalaccessories. The present invention system can also be enabled in thesemodified brick-shaped packages.

FIG. 6 is a schematic block diagram illustrating a phase shift variationof the present invention system. A first phase shifter 600 is shownhaving an input connected to the first transmission line port of theswitch 116 on line 104 a and an input on line 115 a to accept controlsignals from the regulator circuit 112. The first phase shifter 600 hasa plurality of through-signal phase differentiated outputs selectivelyconnected to the first antenna transmission line port in response to thecontrol signals. As shown, the first phase shifter includes threephase-differentiated outputs on lines 104 b, 104 c, and 104 d, separatedby approximately 90 degrees. The word “approximately” is used because offabrication tolerances, which will vary for different manufacturers, andthe fact that the frequencies of interest are typically a band offrequencies, as opposed to a single frequency. The present invention isnot limited to any particular number of phase shifter outputs or anyparticular differentiation in phase.

Likewise, a second phase shifter 602 has an input connected to thesecond transmission line port of the switch and an input on line 115 bto accept control signals from the regulator circuit 112. The secondphase shifter 602 also has a plurality of through-signalphase-differentiated outputs selectively connected to the second antenna110 transmission line port in response to the control signals. Again,three phase-differentiated outputs 106 b, 106 c, and 106 d are shown asan example, separated by approximately 90 degrees.

The present invention system 100 can use the phase shifters 600 and 602to improve communications being received on either a single, switchedantenna, or communications being received combined on antennas. Forexample, the phase can be selected in response to minimizing decodingerrors (FIG. 2) or maximizing received signal power (FIG. 1). Althoughnot specifically shown, the system 100 could also be enabled with just asingle phase shifter interposed between the switch and the transceiver.Such as variation would be more effective when the antennas areswitched, as opposed to combined.

FIG. 7 is a schematic block diagram illustrating an antenna electricallength variation of the present invention system. The system 100comprises a first antenna 108 having an input on line 115 c to acceptcontrol signals, and an active element electrical length responsive tothe control signals. Likewise, the second antenna 110 has an input online 115 d to accept control signals, and an active element electricallength responsive to the control signals. The regulator circuit 112 hasoutputs connected to the first and second antennas on line 115 c and 115d, respectively, to supply control signals in response to transmissionline signals on the first and second transmission line. As above, theregulator circuit can be responsive to power reflected by the antenna,received signal strength, of decoded error rates. Also as above, thisvariation of the system may further incorporate phase shifting elements.

The electrical length of many different antenna styles can be modifiedby using a microelectromechanical switches (MEMSs) to change thephysical length of an active element, such as a radiator, or by using aferroelectric material to change to dielectric constant proximate to anactive element. However, the present invention is not limited to anyparticular active element electrical length modification means.Additional details of the above-described MEMS and ferroelectricantennas can be found in U.S. Pat. App. No. 2004/0246189 (Tran), whichis incorporated herein by reference.

Although not specifically shown, from the figures and the abovedescriptions it can be extrapolated that the present invention maycomprise a plurality of transmission lines and a plurality of antennasinternally mounted to the chassis, each with a transmission line portconnected to a corresponding one of the plurality of transmission lines.Then, the regulator circuit has inputs operatively connected to each ofthe plurality of transmission lines. The switch, likewise, has portsconnected to each of the plurality of antennas to selectively connectthe plurality of antennas to the transceiver port in response to controlsignals from the regulator circuit. As above, the regulator circuit canbe responsive to power reflected by the antenna, received signalstrength, of decoded error rates. Also as above, this variation of thesystem may further incorporate phase shifting elements and/or antennaswith electrical lengths that can be modified.

FIG. 8 is a flowchart illustrating the present invention method fordiversifying radiated electromagnetic communications in a wirelesstelephone device. Although the method is depicted as a sequence ofnumbered steps for clarity, no order should be inferred from thenumbering unless explicitly stated. It should be understood that some ofthese steps may be skipped, performed in parallel, or performed withoutthe requirement of maintaining a strict order of sequence. The methodstarts at Step 800.

Step 802 mounts a first antenna and a second antenna internal to awireless telephone device chassis. Step 804 senses conductedelectromagnetic transmission line signals communicated by the first andsecond antennas. Step 806 selects between the first and second antennasin response to sensing the transmission line signals. In some aspects,selecting between the first and second antennas in Step 806 includescombining the first and second antennas.

In some aspects of the method, sensing transmission line signals in Step804 includes sensing transmission line signal power levels. In someaspects, Step 804 senses the transmission line signal power levels oftransmitted signals reflected by the antennas.

Some aspects of the method comprise a further step. Step 801 receivesradiated signals communicated on the first and second antennas. Then,sensing transmission line signals in Step 804 includes sensing theradiated signals received at the first and second antennas and conductedon the transmission line.

In one variation, Step 804 senses the power levels of the radiatedsignals conducted on the transmission lines. Then, selecting between thefirst and second antennas in response to sensing the transmission linesignals in Step 806 includes selecting the antenna in response to theradiated signal transmission line power levels.

In another variation, sensing the radiated signals conducted on thetransmission line in Step 804 includes receiving and decoding theradiated signals. Then, selecting between the first and second antennasin response to sensing the transmission line signals in Step 806includes selecting the antenna supplying the transmission line signalwith the fewest number of decoded errors.

In some aspects, Step 801 a communicates radiated electromagneticsignals through the first antenna at a first operating frequency. Step801 b communicates radiated electromagnetic signals through the secondantenna at the first operating frequency. Then, mounting the first andsecond antennas internal to a wireless telephone chassis in Step 802includes separating the first and second antennas by an effectivedistance of about a quarter-wavelength of the first operating frequency.The word “about” is used because of fabrication tolerances inherent inbuilding an electrical device, variations in electrical path due to theshape of the proximate dielectric, and the fact that communications aretypically conducted across a band of frequencies, where only a portionof the band can be at a perfect quarter-wavelength relationship. Itshould be understood that the phase “effective distance” means thedistance between antennas that takes into account the effect of theintervening material dielectric constant. In another aspect, Step 801 bcommunicates radiated electromagnetic signals through the second antennaat a second operating frequency, different than the first operatingfrequency.

In other aspects, communicating radiated electromagnetic signals throughthe first antenna at a first operating frequency in Step 801 a includesradiating in a first polarized radiation pattern. Communicating radiatedelectromagnetic signals through the second antenna at the firstoperating frequency in Step 801 b includes radiating in a secondpolarized radiation pattern, orthogonal to the first polarized radiationpattern.

In some aspects of the method, mounting the first and second antennasinternal to a wireless telephone device chassis in Step 802 includesmounting the first antenna and the second antenna in a chassis havingthe dimensions of 4 inches, by 2 inches, by 1 inch, or less.

Some aspects of the method include further steps. Step 808 phase shiftsthe transmission line signals communicated by a first antenna inresponse to sensing the transmission line signals. Step 810 phase shiftsthe transmission line signals communicated by a second antenna inresponse to sensing the transmission line signals. Another aspect of themethod includes yet a further step that may, or may not be combined withSteps 808 and 810. Step 812 changes the electrical length of the firstand second antennas in response to sensing the transmission linesignals.

In some aspects, mounting a first antenna and a second antenna internalto a wireless telephone device chassis in Step 802 includes mounting aplurality of antennas internal to the chassis. Sensing conductedelectromagnetic transmission line signals communicated by the first andsecond antennas in Step 804 includes sensing transmission line signalscommunicated by the plurality of antennas. Then, selecting between thefirst and second antennas in Step 806 includes selecting between theplurality of antennas in response to sensing between the plurality oftransmission line signals.

A system and method has been provided for diversifying radiatedelectromagnetic communications through the use of selectively connectedchassis-embedded antennas. Although the invention has been presented inthe context of a wireless telephone, it should be understood that theinvention has wider application. Further, although specific arrangementsof antennas, switches, phase shifting, and regulating circuitry has beenpresented, it should be understood that alternate arrangements andcombinations of the circuitry could be used to enable the invention.Other variations and embodiments of the invention will occur to thoseskilled in the art.

1. A wireless communication device antenna diversity system, the systemcomprising: a chassis; a transceiver; a first transmission line; asecond transmission line; a first antenna embedded in the chassis, andoperatively connected to the first transmission line; a second antenna.embedded in the chassis, and operatively connected to the secondtransmission line; a regulator circuit comprising an input operativelyconnected to the first transmission line, an input operatively connectedto the second transmission line, and an output to supply control signalsresponsive to conducted electromagnetic transmission line signals on thefirst and second transmission lines; a switch operatively connected tothe transceiver, the first transmission line, and the secondtransmission line, and having an input to receive control signals fromthe regulator circuit, the switch selectively connecting the transceiverto at least one of the first and second transmission lines in responseto the control signals; and, a correction circuit operatively connectedto at least one of the first and second antennas, and operativelyconnected to at least one of the first and second transmission lines,wherein the correction circuit comprises an input to receive controlsignals from the regulator circuit, and is configured to modifyelectrical performance characteristics of at least one of the first andsecond antennas in response to the control signals.
 2. The system ofclaim 1 wherein the regulator circuit supplies control signalsresponsive to transmission line signal power levels reflected from thefirst antenna and the second antenna.
 3. The system of claim 2 furthercomprising an antenna mismatch detector; and wherein the regulatorcircuit further comprises an input operatively connected to the mismatchdetector, the mismatch detector detecting transmission line signal powerlevels reflected from the first antenna and the second antenna.
 4. Thesystem of claim 1 wherein the regulator circuit is configured to receiveradiated signals communicated on the first and second antennas, decodethe received signals, and determine which of the decoded receivedsignals has the fewest number of decoding errors.
 5. The system of claim1 Wherein the correction circuit further comprises a first phaseshifter, situated along the first transmission line, comprising an inputto receive control signals from the regulator circuit, and a pluralityof through-signal phase differentiated outputs selectively connected tothe first antenna in response to the control signals; and, a secondphase shifter, situated along the second transmission line, comprisingan input to receive control signals from the regulator circuit, and aplurality of through-signal phase differentiated outputs selectivelyconnected to the second antenna in response to the control signals. 6.The system of claim 5 wherein the regulator circuit is configured toreceive radiated signals communicated on the first and second antennas,decode the received signals, and determine which of the decoded receivedsignals has the fewest number of decoding errors; and wherein thecorrection circuit is configured to select a phase that minimizesdecoding errors.
 7. The, system of claim 5 wherein the regulator circuitis configured to detect power of received radiated signals communicatedon the first and second transmission lines; and wherein the correctioncircuit is configured to select a phase that maximizes received signalpower.
 8. The system of claim 1 wherein the first antenna comprises afirst active element with a first electric length; and the secondantenna comprises a second active element with a second electricallength; and wherein the correction circuit is configured to modify atleast one of the first and second. electrical lengths.
 9. The system ofclaim 8 wherein the correction circuit further comprises at least onemicroelectromechanical switch configured to change the physical lengthof an active element of at least one of the first and second antennas.10. The system of claim 8 wherein the correct circuit further comprisesa first ferroelectric material proximate to: the first active elementand a second ferroelectric material proximate to the. second activeelement, and wherein the correction circuit is further configured tochange the dielectric constant at least one of the first and secondferroelectric materials.
 11. A method for managing electromagneticcommunications in a wireless communication device having at least afirst antenna and a second antenna embedded in the device, the methodcomprising: sensing conducted electromagnetic transmission line signalscommunicated by the first and second antennas; selecting between the,first and second antennas in response to the sensing conductedelectromagnetic transmission line signals; and, modifying electricalperformance characteristics of at least one of the first and secondantennas in response to the sensing conducted electromagnetictransmission line signals.
 12. The method of claim 11 wherein thesensing conducted electromagnetic transmission line signals communicatedby the first and second antennas comprises sensing the transmission linepower levels of transmitted signals reflected by the antennas.
 13. Themethod of claim 12 wherein the sensing conducted electromagnetictransmission line signals communicated by the first and second. antennascomprises measuring antenna mismatch.
 14. The method of claim 11 thesensing conducted electromagnetic transmission line signals comprises:receiving radiated signals communicated on the first and secondantennas, decoding the received signals, and, determining which of thedecoded received signals has the fewest number of decoding errors. 15.The method of claim 11 wherein the modifying electrical performance ofat least one of the first and second antennas comprises at least one of:phase shifting the conducted electromagnetic transmission line signalscommunicated by the first antenna in response to the sensing conductedelectromagnetic transmission line signals; and, phase shifting conductedelectromagnetic transmission line signals communicated by the secondantenna, in response to the sensing conducted electromagnetictransmission line signals.
 16. The methods of claim 15 wherein thesensing conducted electromagnetic transmission line signals comprises:receiving radiated signals communicated on the first and secondantennas, decoding the received signals, and, determining Which of thedecoded received signals has the fewest number of decoding errors;wherein the phase shifting the conducted electromagnetic transmissionline signals communicated by at least one of the first and secondantennas comprises selecting a phase that minimizes decoding errors. 17.The method of claim 15 wherein the sensing conducted electromagnetictransmission line signals comprises detecting power of received radiatedsignals communicated on the first and second antennas; and, wherein thephase shifting the conducted electromagnetic transmission line signalscommunicated by at least one of the first and second comprises selectinga phase that maximizes power of received radiated signals.
 18. Themethod of claim 11 wherein the modifying electrical performance of atleast one of the first and second antennas comprises changing theantenna electrical length performance of the at least one of the firstand second antennas in response to the sensing conducted electromagnetictransmission line signals communicated by the first and second antennas.19. The method of 18 wherein the changing the antenna electrical lengthcomprises changing the physical length of an active element of at leastone of the first and second antennas via microelectromechanicalswitching.
 20. The method of claim 18 wherein .the changing the antennaelectrical length comprises changing. the dielectric constant of aferroelectric material proximate to an active element of at least one ofthe first and second antennas.